Derrida's Of Grammatology has a section in which he discusses Rousseau on the topic of masturbation (this should get me some interesting hits in search engines).

What I've written elsewhere concerning Derrida has typically concerned more his overall philosophy of language, presence, and difference. But in the second part of Derrida's book, he engages in an extended interaction with Rousseau on the issue of language. In the course of that discussion, Derrida does talk about Rousseau's writings on masturbation, in part, because Rousseau uses the same terminology to discuss it as he does to discuss the nature of language (e.g., "supplementation," "absence," etc.).

Here are a few thoughts, beginning with some historical context since everything, even wanking, has a history.

Starting in the 18th century, Enlightenment philosophy, literature, and science produced a huge literature on masturbation (in philosophy and letters: Voltaire, Kant, Rousseau, Wollstonecraft, Swift, among others). In the 1720s, a Swiss physician named Samuel Tissot wrote a 400 page book on the topic as a medical problem, suggesting that the practice could have all sorts of terrible consequences for bodily health.

His book was highly influential and the topic came into the literature, often intertwined with all kinds of other issues, philosophical and medical. Kant, for instance, gave an extended discussion of its irrationality and concluding that masturbation is both absurd and ethically worse than suicide.

The issue thus quickly turned from one of sympathetic pastoral concern to something that occupied a large place in modern medicine, educational practices, psychological liturature, and was accompanied by the introduction of various forms of regulation and monitoring, as well as a huge anxiety that was actually quite a new thing, historically.

As part of postmodernism's critique of the modern, and the Enlightenment in particular, there has been some attention to the issue (e.g., in Foucault's History of Sexuality), especially the question of why it came to occupy such a large place in the modern mind (as opposed to the premodern) and how this is intertwined with wider issues of epistemology, ethics, and so on.

Commentators, of course, have long explored the connection between modernist philosophy and the kinds of chauvinism and misogyny that were typical of many Enlightenment figures. For instance, it is a commonplace that Descartes' skeptical attitude toward that which is "other"--the world of nature, traditionally conceived in feminine categories--has significant implications for the sterility and misygony of modernist epistemologies (one author uses Othello's growing doubts concerning Desdemona as a way of painting Descartes as a philosophical Iago).

The way in which these issues arise for Derrida is in his discussion of Rousseau. Derrida is discussing the tradition that speech is somehow more basic than writing, attempting to undo the binary opposition in which speech and writing are opposed to one another and speech is then valorized over writing.

To review, on the traditional perspective, writing is a sign pointing to speech and speech is a sign pointing to thought. Speech, therefore, was traditionally considered as better than writing since it was more immediate and connected with the personal presence of the speaker, clearly communicating his own mind, while writing was a way of preserving speech in absence of the speaker. Moreover, speech was traditionally thought to remain interior to or in the possession of the speaker, while a written text is exterior to the author and can be wrested free from his intentions.

But this privileging of speech over writing presupposes what Derrida calls a "metaphysics of presence," whether the presence of meaning to the mind (as with Descartes' clear and distinct ideas) or of objects to the senses (so the mind can transparently mirror the world). This is a desire for a "transcendental signified," something that exists outside of all signifiers and is transparently referred to by them.

According to Derrida, however, reality is constituted by what he calls "differance," a word he coins that plays on the French terms for "differing" and "deferring"--a pun, by the way, which is evident in its writing, but unnoticable in speech. Derrida uses the term, among other things, in order to suggest that for something to be what it is, it must be different from something else. Yet that difference is registered only by a "trace" of those things from which it is different, marking the presence of those things even in their absence. Thus there is no possibility of either absolute presence or absolute absence, leaving an interplay in which absolute presence is continually deferred.

In terms of language and meaning, part of what this suggests is that the meaning of texts is something that only arises through the articulation of difference among words and other texts. But this, in turn, indicates that meaning is never absolutely present, but is continually deferred as it plays itself in relation to other absent texts, which are present in traces by the very registering of their absence.

Derrida's point about writing and speech, is that on the traditional picture, writing is second-rate because it is at a double-remove from ideas in the mind of its author: ideas turned into speech turned into writing. Thus writing, on the traditional view, consists merely in signs pointing to yet other signs.

But, if Derrida is correct about differance--about the nature of signs and meaning and language in general--then all language is "writing," that is, signs pointing to yet other signs. Speech cannot be privileged over writing, since even the spoken word is fully implicated within a system of signs that pre-exists the speaker. Presence and absence are at play in speech as much as in writing and (finalized, fully expressed, comprehensive) meaning is deferred.

Rousseau is relevant to this because he discusses the topic of speech and writing himself, representing the wider tradition, speaking of writing as a "supplement" to speech, something designed to substitute for and make up for the lack of speech due to the absence of the speaker (and thus writing can become--in his view unfortunately--necessary). But writing, insofar as it is a kind of perverse addition to speech, does nothing to add to, change the nature of, or affect speech (and thus becomes superfluous). This tension is apparent in the French term "supplement," which can mean not only a "substitute" but also an "addition."

But Rousseau uses all this same language in his discussion of masturbation as well, speaking of it as a "dangerous supplement," a perverse addition which does not affect the nature of normal sexuality. Thus it substitutes for, or takes the place of, normal sexual activity in the absence of the other. But given how Rousseau uses the terminology of "supplement," it would seem that logically, autoerotic activity could also be seen as a necessary extension of sexuality, something that could even replace its normal expression and in which the other would be present in even absence. Indeed, Rousseau, in Emile, discusses this danger, suggesting that unless children are stopped from engaging in these practices, they will never marry.

Derrida uses the example of Rousseau's discussion of speech and writing, as well as his discussion of masturbation, to show the ways in which Rousseau's own terminology and way of framing things tends to undermine itself at some point, or slip off into meanings or implications that Rousseau didn't intend. So, while Rousseau seems to want to say that these supplementations are purely negative, his way of saying it seems to say otherwise. For instance, his critique of writing is, after all, written and his discussion of sexuality allows for supplementary practices to be fulfilling.

Derrida uses this dynamic to critique Rousseau's approach to language and support his own way of seeing things regarding language, his notion of "differance" and what he also terms (deploying something of a pun, given the context), the "dissemination" of meaning.

Theologically, I think there is something to be learned from Derrida's discussion here, as well as the history of the past 400 years or so. Much of Derrida's linguistic point is well taken, particular by Christians who do have a written text as central to our whole way of life, even if that text is also one that must be proclaimed and heard and enacted (which I've discussed here before).

Even on the issues of sexuality, Derrida may well be helpful in better thinking through how we frame issues of morality, placing them in a larger context. For example, as has been pointed out by a number of theologians, Romans 1 seems to present the rejection of the sexually "other" and "different" as of the essence of original sin, a created reflection of the rejection of the ultimate "otherness" of God and the "difference in unity" that is the Trinity. Thus, medieval Christian confessional manuals were correct in seeing all forms of sexual sin (fornication, promiscuity, etc) as incipiently "homosexual" in their structure, unless redeemed through marriage and openness to procreation. Otherwise, the object of sexuality is turned into an anonymous and narcissistic object that is, in principle, exchangeable with any other, thereby effacing its "otherness."

If it is indeed the case that our modernist epistemologies and ontologies contain the kinds of deep ambiguities that Derrida suggests with regard to "otherness" and "supplementation," then it may be no accident that, as those assumptions have moved into their phase of decadance, that they have given rise to an increasingly pornographized and sexually narcissistic society and culture. There are issues to explore there, but I haven't yet thought them through sufficiently, though there is a significant literature on the topics.